The long-term goal of this proposed research is to characterize specific changes in the structural and functional organization of cell membranes that occur with changes in hormone stimulation. We intend to develop a general method of spontaneous vesiculation of nucleated cell membranes so that purified membrane vesicles may be isolated which retain their hormone sensitive adenylate cyclase activity. These purified plasma membranes will be characterized for their protein composition, glycoprotein content and phospholipid composition. Catecholamine binding studies will be used to chracterize the hormone -membrane receptor interaction, and spectroscopy will be used to delineate subsequent membrane changes which occur with catecholamine binding. Plasma membranes will be isolated from the human lung fibroblast, WI-38; its transformed counterpart, VA-13, from the human astrocytoma cell line, 132-IN1, and from avian erythrocytes. These cell lines will be used to determine the general applicability of this method of membrane vesicle isolation to nucleated cells; to correlate general structural components in these various cell types; and, to determine and variations in receptor-catecholamine interactions in different membranes. The catecholamine - membrane receptor interaction will also be investigated in model membrane systems by spectroscopy. Isolated receptor macromolecules will be reincorporated into hormone insensitive vesicles and artificial lipid vesicles to characterize the molecular events in the hormone-receptor interaction. Erythrocyte membrane vesicles will also be used as model systems to study membrane structural changes and their relation to membrane function. BIBLIOGRAPHIC REFERENCES: R.F. McGuire and R. Barber. Hormone Receptor Mobility and Catecholamine Binding in Membranes. A Theorectical Model. J. Supramol. Structure 4, 259 (1976). R.F. McGuire and R.B. Clark. Isolation of Two Populations of Plasma Membrane Vesicles from Cultured Human Glioma Cells with Epinephrine and Adenosine Sensitive Adenylate Cyclase. Abstract. Fed. Proc. 35, #1368 (1976).